1. Technical Field
The present invention relates to an aqueous ink composition and a recorded article that is formed by using such a composition.
2. Related Art
In typical, the following techniques have been employed as a technique by which a coating film having metallic gloss is formed on a printing medium: a technique which utilizes a printing ink containing gold powder or silver powder that is prepared from brass particles, aluminum particles, or the like as a pigment; foil stamping printing which utilizes metal foil; and a thermal transfer technique which utilizes metal foil.
In recent years, these techniques have been frequently applied to ink jet printing. In an example of such applications, metallic printing is employed, and development of an ink having metallic gloss has been advanced. For example, JP-A-2008-174712 discloses an aluminum pigment dispersion liquid which contains an organic solvent, such as alkylene glycol, as a basic component and discloses a nonaqueous ink composition containing such an aluminum pigment dispersion liquid.
On the other hand, in terms of global environment and impact on the human body, development of an aqueous ink composition is actually desired rather than development of the organic solvent-based nonaqueous ink composition. In the case of using an aqueous ink, a humectant is generally added in terms of adjusting the viscosity of the aqueous ink and preventing the aqueous ink from being dried in a printer.
However, in the case of using an aqueous ink containing silver particles as a metallic pigment, a problem is caused, in which the metallic gloss of an image that is recorded on a recording medium is significantly varied depending on types of the humectant to be added.